Siloxane-Based Coating Material, Optical Article, and Production Method of Siloxane-Based Coating Material

Abstract

The invention provides a coating material containing silica fine particles, a siloxane compound, and a curing agent and giving an even coating film in the case it is used for forming a coating film. The invention gives a siloxane-based coating material excellent in storage stability and giving high surface hardness of a coating film when the coating material is used for forming the coating film. The invention also provides an optical article excellent in anti-reflection property and scratching resistance.

1 . A siloxane-based coating material comprising silica fine particles, a siloxane compound, and a curing agent, wherein a coating film formed using the coating material has evenness.  
     
     
         2 . The siloxane-based coating material according to  claim 1  further comprising a solvent having a boiling point of 100 to 180° C. in atmospheric pressure and a solvent having a boiling point of lower than 100° C. in atmospheric pressure.  
     
     
         3 . The siloxane-based coating material according to  claim 1 , wherein the siloxane compound is a hydrolyzed product and/or a condensation product of one or more silane compounds selected from compounds defined by the following formulas (1) to (5):  
         R 1 Si(OR 6 ) 3   (1)  
       wherein R 1  denotes a fluoroalkyl group having 3 to 17 fluorine atoms; and R 6  denotes a methyl group, an ethyl group, a propyl group, an isopropyl group, or an acetyl group and all may be the same or different;  
         R 2 Si(OR 7 ) 3   (2)  
       wherein R 2  denotes a group selected from a vinyl group, an allyl group, an alkenyl group, an acryl group, a methacryl group, a methacryloxy group, a cyano group, an epoxy group, a glycidoxy group, an amino group, and their substituted groups; and R 7  denotes a methyl group, an ethyl group, a propyl group, an isopropyl group, a methoxymethyl group, or an acetyl group and all may be the same or different;  
         R 3 Si(OR 8 ) 3   (3)  
       wherein R 3  denotes hydrogen or a group selected from an alkyl group, an aryl group, and their substituted groups; and R 8  denotes a methyl group, an ethyl group, a propyl group, or a butyl group and all may be the same or different;  
         R 4 R 5 Si(OR 9 ) 2   (4)  
       wherein R 4  and R 5  independently denote hydrogen or a group selected from an alkyl group, a fluoroalkyl group, an aryl group, an alkenyl group, a methacryloxy group, an epoxy group, a glycidoxy group, an amino group, and their substituted groups and may be the same or different; and R 9  denotes a methyl group, an ethyl group, a propyl group, an isopropyl group, or an acetyl group and all may be the same or different; and  
         Si(OR 10 ) 4   (5)  
       wherein R 10  denotes a methyl group or an ethyl group and all may be the same or different.  
     
     
         4 . The siloxane-based coating material according to  claim 1 , wherein the number average particle diameter of the silica fine particles is in a range from 1 nm to 200 nm.  
     
     
         5 . The siloxane-based coating material according to  claim 1 , wherein the silica fine particles are silica fine particles having cavities in the inside.  
     
     
         6 . The siloxane-based coating material according to  claim 1 , wherein the curing agent is an aluminum chelate compound and/or a magnesium chelate compound.  
     
     
         7 . The siloxane-base coating material according to  claim 1  further comprising a fluorine-containing silane compound defined by the formula (1):  
         R 1 Si(OR 6 ) 3   (1)  
       wherein R 1  denotes a fluoroalkyl group having 3 to 17 fluorine atoms; and R 6  denotes a methyl group, an ethyl group, a propyl group, an isopropyl group, or an acetyl group and all may be the same or different.  
     
     
         8 . The siloxane-based coating material according to  claim 1  further comprising a fluorine-containing silane compound defined by the formula (2):  
         R 2 Si(OR 7 ) 3   (2)  
       wherein R 2  denotes a group selected from a vinyl group, an allyl group, an alkenyl group, an acryl group, a methacryl group, a methacryloxy group, a cyano group, an epoxy group, a glycidoxy group, an amino group, and their substituted groups; and R 7  denotes a methyl group, an ethyl group, a propyl group, an isopropyl group, a methoxymethyl group, or an acetyl group and all may be the same or different.  
     
     
         9 . The siloxane-based coating material according to  claim 1 , wherein the coating film has a refractive index in a range from 1.25 to 1.4.  
     
     
         10 . A coating film obtained by curing the coating material according to  claim 1 .  
     
     
         11 . An optical article having a coating film formed on a transparent substrate by using the coating material according to  claim 1 .  
     
     
         12 . An optical article having a siloxane-based coating film formed on a transparent substrate, wherein the element content ratio of tetrafunctional silicon in entire silicon is in a range from 0.3 to 0.6; the content ratio of fluorine to silicon is in a range from 0.4 to 0.65 in the coating film and the coating film has a refractive index in a range from 1.25 to 1.4.  
     
     
         13 . The optical article according to  claim 12  comprising silica fine particles in the coating film.  
     
     
         14 . The optical article according to  claim 13 , wherein the silica fine particles having cavities in the inside.  
     
     
         15 . The optical article according to  claim 12 , wherein the thickness of the siloxane-based coating film is in a range from 0.001 to 0.5 μm and the number average particle diameter is smaller than the thickness of the siloxane-based coating film.  
     
     
         16 . The optical article according to  claim 12 , wherein the siloxane based coating film becomes even.  
     
     
         17 . The optical article according to  claim 12 , wherein the siloxane-based coating film further contains an aluminum compound and/or a magnesium compound.  
     
     
         18 . The optical article according to  claim 12 , wherein the transparent substrate is a film.  
     
     
         19 . The optical article according to  claim 12 , comprising a high refractive index layer having a refractive index of 1.45 to 2.0 between the transparent substrate and the siloxane-based coating film.  
     
     
         20 . The optical article according to  claim 12 , wherein the transparent substrate has a hard coat layer with a thickness of from 0.2 to 20 μm.  
     
     
         21 . A production method of a siloxane-based coating material, comprising a step of hydrolyzing a silane compound in a solvent by an acid catalyst in the presence of silica fine particles and successively subjecting the hydrolyzed product to condensation reaction.  
     
     
         22 . The production method of a siloxane-based coating material according to  claim 21 , wherein the silane compound is one or more silane compounds selected from silane compounds defined by the following formulas (1) to (5):  
         R 1 Si(OR 6 ) 3   (1)  
       wherein R 1  denotes a fluoroalkyl group having 3 to 17 fluorine atoms; and R 6  denotes a methyl croup, an ethyl croup, a propyl group, an isopropyl group, or an acetyl group and all may be the same or different;  
         R 2 Si(OR 7 ) 3   (2)  
       wherein R 2  denotes a group selected from a vinyl group, an allyl group, an alkenyl group, an acryl group, a methacryl group, a methacryloxy group, a cyano group, an epoxy group, a glycidoxy group, an amino group, and their substituted groups; and R 7  denotes a methyl group, an ethyl group, a propyl group, an isopropyl group, a methoxymethyl group, or an acetyl group and all may be the same or different;  
         R 3 Si(OR 8 ) 3   (3)  
       wherein R 3  denotes hydrogen or a group selected from an alkyl group, an aryl group, and their substituted groups; and R 8  denotes a methyl group, an ethyl group, a propyl group, or a butyl group and all may be the same or different;  
         R 4 R 5 Si(OR 9 ) 2   (4)  
       wherein R 4  and R 5  independently denote hydrogen or a group selected from an alkyl group, a fluoroalkyl group, an aryl group, an alkenyl group, a methacryloxy group, an epoxy group, a qlycidoxy group, an amino group, and their substituted groups and may be the same or different; and R 9  denotes a methyl group, an ethyl group, a propyl group, an isopropyl group, or an acetyl group and all may be the same or different; and  
         Si(OR 10 ) 4   (5)  
       wherein R 10  denotes a methyl group or an ethyl group and all may be the same or different.